Dublo Light Signals

I have quite an extensive layout that I am signalling with Dublo light
signals powered from 3 number H & M Duet controllers. Power being take from
the 16 volt side. Can anybody please advise me how many bulbs/signals I can
safely run from each power sauce? I do not of cause want to toast the whole
system. Many thanks Roger.
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Roger Mitchell
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To calculate the number of bulbs you can run: Check the specs of the power supplies you will use, which should be printed on a panel on the case itself. Output is rated in DC and/or AC volts under maximum load(s), which will be the rated safe maximum amperage. They should also show wattage, but if that's not shown, multiply amps times DC volts, or amps times 2/3rds AC volts. (Not exact for AC, but good enough for low voltage AC.) Keep in mind controlled and uncontrolled outputs come from one transformer, so if you use more train power, you'll have to use less signal power, and vice-versa. That's why I disrecommend using one source for both trains and lighting/signalling.
The problem is the HD lamps. If they are the originals, then they will draw around 2-3 watts each IIRC (it's been decades since I played with HD.) That's a lot! In fact, the lamps will get hot enough to be painful to touch, and will melt nearby plastic. Assume 3 watts, and divide the rated wattage by that number. The result should be a safe number.
Now for relevant information that you didn't ask for ;-) :
Firstly, you won't toast the whole thing. The power supplies are protected with fuses or overload shut-offs. If you overload them, they will simply shut down. So the simplest thing is just to keep adding bulbs (signals) until the power supply starts complaining. Just let it run for 5 -10 minutes, and test it with your hand. It should be warm, but not hot.
Secondly: I hope you use power supplies either for train running or signalling, not both. Any power drawn for trains will not be available for signals, and vice versa.
Thirdly: make sure that you don't supply excess voltage to the bulbs. They will draw as much power as you give them, to the point of suicide. At higher voltages, they draw more power. At rated voltages, they have a limited life. If the nominal rating is 16V, run them at 12V or less. Best: use series-parallel wiring so that the bulbs "see" only 8 volts. They will burn dimmer, but will last pretty well indefinitely.
Fourthly: the Duette does not meet current safety standards, so I hope you know what you're doing. Main problem IIRC: the overload shut-off is too slow for safety.
HTH wolf k.
Reply to
Wolf K
Well,if you have lots then the sauce will have to be high power,commonly available as HP Sauce. I find it goes quite well with Toast anyway.
Seriously,ISTR that the Duett can put out about 1 amp,so with 3 you have 3 amps available if you are just using them for the signals. Not sure what lamp the old Hornby Dublo signals have but a modern grain of wheat lamp is about 80mA . 1 amp is 1000mA so you could run 37 lamps of your 3 duettes with a small margin. However most grain of wheat lamps are for 12 volts and would not last too long on the 16 volt side. Even 12 volt ones are best run at something like nine Volts to extend their life. Most households now have a wall wart or two lying in a drawer from some appliance that has broken. often they are 6 or 9 volt and could power a few signals.
Reply to
Hi Many thanks for the advice re Dublo light signals. A few months ago I aquired an "Irwin Central Power Sauce". Which has a 30 amp 16 volt controlled output, with adjustable load trip & a current flow dial. This is now installed & the voltage turned down to about 10 volts to make the lamps last longer. All seems to be working very well. giving me a seperate power suppy from the running side. My Duet 16 volt supply is now dedicated to turnout duties only. Many thanks Roger
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